John thompson



(No Model.)

J. THOMPSON.

DREDGING MACHINE.

N0.'341,611. Patented May 11, 1886.

UNITED STATES PATENT OFFICE.

JOHN THOMPSON, OF BUOYRUS, OHIO, ASSIGNOR TO THE BUOYRUS FOUN- DRY AND MANUFACTURING COMPANY, OF SAME PLACE.

MACHINE.

SPECIFICATION forming part of Letters Patent No. 341,611., dated May 11, 1886,

Serial No. 181,093. (No model.)

To all whom it may concern.-

Be it known that 1, JOHN THOMPSON, a citizen of the United States, and a resident of Bucyrus, in the county of Crawford and State of Ohio, have invented certain new and useful Improvements in Dredging-Machines, of which the following is a specification.

My invention relates tonew and useful devices by the employment of which the downhaul or backing chain and the hoisting-chain used in dredging-machines may be made to run more smoothly and with less noise and friction than as heretofore constructed, the chains being so guided as not to affect the swinging of the bucket or boom, and so as to come straight to their respective winding drums irrespective of the position of the boom or bucket.

Figure 1 illustrates a side elevation of the invention. Fig. 2 illustrates a front elevation of the invention in detail, the mast and boom being broken off. Fig. 3 illustrates a front elevation, the boom being swung outward. Fig. 4. illustrates a front view showing the grooved sheave i and its supporting hangers or arms, and also in dotted lines the sheaves I and i when shifted on the shaft J.

The same reference-lettersindicate the same parts in all the figures.

A is the float. B is the mast. C is a frame erected on the float for the support of parts of the mechanism. D is the turning or swing ing frame rotated by suitable draft-chains or equivalent devices. E is the bucket-carrying gaff. F is the boom. G is thehoisting chain. H is the down-haul chain.

In order that the down-haul and hoisting chains may notinterfere with the swinging of the boom, it is desirable that they should both come from their respective points of contact with the end of the boom and the bucket or gaff E (depending on whether the downhaul chain is attached to the bucket or to the gaff near the bucket) direct to the center of motiOn-in other words, to the 1nastin straight lines, and then being deflected. there proceed thence in other straight lines to the windingdrums,on which they respectively are wound by the engine. Various devices have heretofore been used for this purpose, which have been open to various objections, especially the great friction and wear of parts at the point of deflection-to wit, at or near the mast-and consequent great power required to operate them in certain positions of the boom. By my invention I overcome these difficulties in a comparatively inexpensive and very simple and durable manner, and the chains, irrespective of the position of the boom, may be drawn in and wound up on their drums quickly and without friction, and with the expenditure of comparatively little power.

Referring first to the down'haul chain, I is a slip-sheave grooved on its edge and placed on a shaft, J, which is fastened between the lower ends of the two parts of the boom-if it be made in two partsor otherwise suitably supported if the boom be asolid one. The sheave runs loosely on the shaft J, so that it can slip lengthwise oft it'from side to side as moved by the lateral pressure of the downhaul chain.

K K are two horizontallyacting grooved .sheaves set edge to edge, and which turn on vertical pins or shafts,set in a suitable frame,L, orother suitable support which is fastened at or near the foot of the mast. The grooves in the sheaves K K come quite close together, leaving a hole or space, M, formed by the grooves in the sheaves between them. This hole is in front of and on a level with a corresponding hole, 0, made directly through the mast, and a grooved sheave, N, set vertically is placed on the opposite side of the mast from the sheaves K K. The upper side of this sheave N is about on a level with the hole 0 through'the mast. The down haulchain H passes from the winding-drum forward over the sheave N, through the hole 0 in the mast, between the sheaves K K, under the'sheave I, and thence upwardly, and is attached to the bucket or the gaff E, as usual.

It will sometimes happen, owing to the gaff E being drawn back very near to the bow of the float, or because of considerable depth of water in which the dredging is being done, that the down-haul chain will be carried so low when the bucket is swung for refilling as to leave the sheave I, and when the bucket is lifted again the chain might not be in such a position as to properly enter the groove in the sheave I. I overcome this difficulty as follows: By the side of the sheave I and hanging loosely on the shaft J, I provide two downwardly-extending arms or hangers, zi'one on each side of the sheave I,with a cross-pin at their lower endsupon which turns another grooved sheave,i. The groove in this sheave is of sub stantially the same size as thatin the sheave I, and their edges run quite close together, leaving a circular space between them, similar to the space M between the sheavesKK,through which the down-haul chain passes. This lower sheave, i, performs no function so long as the down-haul chain rests in the groove of the sheave I; but so soon asit leaves that groove it is caught by the groove in the sheave i, and is then permanently held in proper relation to the sheaves I and K K. The hangers i t" and the sheave i,supported on them, are carried with the sheave I to the right and left, sliding on the shaft J ,as that sheave is pressed in one direction or the other by the lateral pressure of the down-haul chain, as before stated. I have not illustrated this hanging sheave or its supports i i in Fig. 2 of the drawings, because they would obscure view of the relation of the parts in rear thereof.

Referring now to the hoisting-chain G. a verticallyacting grooved sheave,P, rotates in suitable bearings fixed on the swinging frame D, the rearward edge of this wheel being substantially on a line with the axis of the mast. A hole, Q, is made through the mast from its top down to a grooved sheave, R, which rotatesin suitable bearings attached,preferably, to the rear side of the mast. The inner edge of this sheave is substantially on a line with the centerof the hole Q through the mast, an opening or slot, S, being made through the rear side of the mast for the sheave to work in.

It will thus be seen, referring to the downhaul chain, that whatever the position of the boom may be, all the points of divergence from straight lines of the chain H will be provided with a freely-rotating sheave, over which this chain may pass to the winding-drum. The sheaves I and i will always smoothly and easily afford vertical divergence, the sheaves slipping on the shaft J to the right or left, as required by the lateral pressure of the chain against the sides of the groove formed in their edges, and one or the other of the sheaves K K, depending upon whether the boom is swung to the right or-to the left, will always afford smooth and easy lateral divergence for this chain, and it will thus be guided directly into the hole through the mast and will then pass in a straight line to the wind ing-drum.

The sheaveN is intended to receive the slack of the chain H during the operation of hoisting, at which time the chain is apt to be quite slack, and guides it straight through the hole in the mast on its reverse movement, thus avoiding friction, wear, and jamming of the chain against the sides of the holein the mast.

Referring to the hoisting'chaiu G, thesheave P, which swings with the frame D, will guide the chain down through the hole in the mast to and over the sheave R, passing over which it will be deflected straight to its windingdrum. The mast is of course rigid, and the frame D and boom Fturn on suitable turntables or like devices, X X, at or near the top and bottom of the mast.

I do not limit myself to the details of construction shown, since it will be obvious to any one familiar with this art that they may be quite extensively varied and still my invention be employed.

1. The combination,in adredge or like machine, of a sheave supported on and swinging with the boom, adapted to give vertical deflection to the down-haul chain, two stationary sheaves placed edge to edge, adapted to give lateral deflection to the down-haul chain, and mechanism for winding up the down-haul chain, substantially as and for the purposes set forth.

2. The combination,in a dredge or like machine, of a sheave, I, capable of sliding laterally on its shaft, supported on and swinging with the boom, horizontally acting sheaves K K, sheave N, and winding mechanism for the down-haul chain, substantially as and for the purposes set forth.

3. The combinatiomin a dredge or like machine, of a sheave, I, capable of sliding laterally on its shaft, supported on and swinging with the boom, horizontally-acting sheaves K K, an unobstructed space for the passage of the chain from the sheaves K K to the winding mechanism, and winding mechanism for the down haul chain, substantially as and for the purposes set forth.

4. The combination, in a dredgingmachine, of a swinging boom, a grooved sheave, I, supported by said boom and swinging therewith, another grooved sheave placed beneath the sheave I and running edge to edge therewith and moving laterally with the sheave I, and means for supporting the lower sheave, substantially as and for the purposes set forth.

5. The combination in a dredging-machine, of a swinging boom, a grooved sheave, I, an under hanging sheave, i, sheaves 'K K and N, and an open space through the mast for the passage of the down-haul chain, all combined and operating substantially as and for the purposes set forth.

Signed at New York, in the county of New York and State of New York, this 23d day of October, A. D. 1885.

JOHN THOMPSON.

Witnesses:

JOHN H. IvEs, J OHN J. CAULDVVELL. 

